Fluid Delivery Catheter with Pressure-Actuating Needle Deployment and Retraction

ABSTRACT

A fluid delivery catheter that uses micro-needles for fluid delivery though a vessel wall. The catheter may provide fluid delivery therapy for various procedures, such as, for example, delivery of tumescent fluid or renal denervation. The catheter includes an elongate member with deployable and retractable needles disposed about a distal end of the elongate member. The needles may be disposed radially about the distal end and/or along a length of the distal end.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional application of U.S. patentapplication Ser. No. 13/826,237, entitled Fluid Delivery Catheter withPressure-Actuating Needle Deployment and Retraction, filed Mar. 14,2013, the complete disclosure of which is incorporated herein byreference for all purposes.

TECHNICAL FIELD

The present embodiments relate generally to therapy for hollowanatomical structures, and more specifically to a fluid deliverycatheter with pressure-actuated needle deployment and retraction.

BACKGROUND

Many medical procedures are conducted within or around a body vessel,such as a blood vessel. Such procedures often require the delivery of atherapeutic fluid or agent to a length of the vessel or around thevessel. For example, treatment of varicose veins may require thedelivery of a tumescent fluid around a length of a blood vessel tocompress the blood vessel around and onto a therapeutic device withinthe blood vessel lumen. Similarly, to treat varicose veins, a sclerosantmay be injected along the length of a blood vessel to irritate andeventually close the blood vessel.

In other procedures, a drug may be delivered along the length of avessel to affect various tissue in and around the vessel. For example,in renal denervation, which is a procedure to lower blood pressure, adrug may be delivered to the renal artery to affect the nerves in oraround the vascular wall.

Delivery of the therapeutic fluid along a length of the vessel is oftenan issue. For example, therapeutic fluid may be delivered subcutaneouslyaround the vessel, such as injecting tumescent fluid around a vein forvaricose vein treatment, which requires multiple injections along thelength of the vein. Injection of a therapeutic fluid from within thevessel lumen often requires moving a single needle along and around thevessel lumen to provide enough of the therapeutic fluid. Both are timeconsuming, requiring significant manipulation and multiple injections atmultiple sites. Therefore, a more effective device to inject therapeuticfluid along a length or around a body vessel is needed.

SUMMARY

The various embodiments of the present apparatus and methods haveseveral features, no single one of which is solely responsible for theirdesirable attributes. Without limiting the scope of the presentembodiments as expressed by the claims that follow, their more prominentfeatures now will be discussed briefly. After considering thisdiscussion, and particularly after reading the section entitled“Detailed Description,” one will understand how the features of thepresent embodiments provide the advantages described herein.

The present disclosure provides a fluid delivery catheter withpressure-actuated needle deployment and retraction that enables multipleinjections along and/or around a hollow anatomical structuresimultaneously.

In general, in one aspect, the implementation of the disclosure featuresan apparatus for delivery of a fluid at a treatment site. The apparatusincludes an elongate catheter having an outer sleeve defining atreatment length at or near a distal end of the catheter. The outersleeve defines a plurality of spaced apertures and an outer sleevelumen. The apparatus also includes a flexible inner lining disposedwithin the outer sleeve lumen and defines a plurality of independentlypressure-deformable portions and a lining lumen. Each of the pluralityof pressure deformable portions is generally aligned with one of theplurality of spaced apertures. A plurality of micro-needles are securedto the pressure-deformable portions and are in fluid communication withthe lining lumen. The pressure-deformable portions and the micro-needlesare recessed beneath an outer surface of the outer sleeve in an at-restconfiguration, and the pressure-deformable portions are deformable to anextended position in which at least a portion of the micro-needlesprotrude above the outer surface of the outer sleeve.

One or more of the following features may be included. Thepressure-deformable portions may be deformed to the extended position bya pressurized fluid delivered into the lining lumen. Alternatively, oradditionally, the pressure-deformable portions may be deformed to theextended position by an elongate wire that includes annular groovesand/or longitudinal grooves. Further, the pressure-deformable portionsmay be biased radially inward.

The pressure-deformable portions may be spaced from one another along alongitudinal axis of the treatment length and/or about a circumferenceof the treatment length. In embodiments, the spacing and position of thepressure-deformable portions trace a helix about the treatment length.

Further, the pressure-deformable portions may be shaped as a conicalfrustum. Each of the micro-needles may be secured to a base of each ofthe frustums. Also, a distal end of the catheter may be closed.

In general, in another aspect, the implementation of the disclosurefeatures an apparatus for delivery of a fluid at a treatment site thatincludes an elongate catheter having an outer sleeve defining atreatment length at or near a distal end of the catheter. The outersleeve defines a plurality of spaced apertures and an outer sleevelumen. A flexible inner lining is disposed within the outer sleeve lumenand defines a plurality of independently pressure-deformable portionsand a lining lumen, wherein each of the pressure deformable portions areshaped as a conical frustum that is biased radially inward andpositioned to generally aligned with one of the plurality of spacedapertures. A plurality of micro-needles are secured to a base of thefrustum of the pressure-deformable portions and are in fluidcommunication with the lining lumen. The pressure-deformable portionsand the micro-needles are recessed beneath an outer surface of the outersleeve in an at-rest configuration, and the pressure-deformable portionsare deformable to an extended position in which at least a portion ofthe micro-needles protrude above the outer surface of the outer sleeve.

One or more of the following features may be included. Thepressure-deformable portions may be deformed to the extended position bya pressurized fluid delivered into the lining lumen. Alternatively, orin addition, the pressure-deformable portions may be deformed to theextended position by an elongate wire that includes annular groovesand/or longitudinal grooves.

In general, in another aspect, the implementation of the disclosurefeatures a method of delivering a fluid at a treatment site within ahollow anatomical structure (HAS). The method includes positioning atreatment length of an elongate catheter at the treatment site. Thetreatment length includes an outer sleeve defining a plurality of spacedapertures and a sleeve lumen. The treatment length further includes aflexible inner lining defining a plurality of independentlypressure-deformable portions and a lining lumen disposed within thesleeve lumen. Each of the plurality of pressure deformable portions aregenerally aligned with one of the plurality of spaced apertures. Thetreatment length further includes a plurality of micro-needles, eachmicro-needle being secured to one of the pressure-deformable portionsand is in fluid communication with the lining lumen. Thepressure-deformable portions and the micro-needles are recessed beneathan outer surface of the outer sleeve in an at-rest state. The methodfurther includes deforming the pressure-deformable portions to anextended position in which at least a portion of the micro-needlesprotrude above the outer surface of the outer sleeve to penetrate a wallof the HAS. The method also includes delivering the fluid under pressureinto the lining lumen, through needle lumens of the micro-needles andinto the HAS wall.

One or more of the following features may also be included. Thepressure-deformable portions may be deformed to the extended position bythe pressurized fluid delivered into the lining lumen. Alternatively, orin addition, the pressure-deformable portions may be deformed to theextended position by an elongate wire that includes annular groovesand/or longitudinal grooves.

The therapeutic fluid flows into the HAS wall at a plurality oflocations simultaneously that correspond to positions of the pluralityof micro-needles.

Further, ceasing delivery of the therapeutic fluid may cause thepressure-deformable portions to retract radially inward such that themicro-needles are again recessed beneath the outer surface of the outersleeve to enable removal of the elongate catheter.

The pressure-deformable portions may be spaced from one another along alongitudinal axis of the treatment length and/or about a circumferenceof the treatment length. In embodiments, the pressure-deformableportions trace a helix about the treatment length.

In various methods, tumescent anesthesia may be injected to thetreatment site prior to delivering the therapeutic fluid under pressure.

The disclosure may be implemented to realize one or more of thefollowing advantages. The elongate catheter can deliver fluid tomultiple injection sites simultaneously with minimal manipulation. Theelongate catheter may be used to inject various fluids, such asanesthesia, sclerosant agents, or medicants. The retractable needlesenable a reduced diameter of the elongate catheter for delivery intovarious hollow anatomical structures. The micro-needles may be sized toinject fluid into the hollow anatomical structure or to tissue outsidethe hollow anatomical structure. Other features and advantages of theinvention are apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments now will be discussed in detail with an emphasison highlighting the advantageous features. These embodiments are forillustrative purposes only. These drawings include the followingfigures, in which like numerals indicate like parts:

FIG. 1 is a side perspective view of a fluid delivery catheter accordingto the present embodiments;

FIG. 2 is a detail view of the portion of the fluid delivery catheter ofFIG. 1 indicated by the circle 1-1, showing the micro-needles in aretracted position;

FIG. 3 is a cross-sectional view of the portion of the fluid deliverycatheter of FIG. 2;

FIGS. 3A and 3B are cross-sectional views of alternative configurationsfor the fluid delivery catheter of FIG. 2;

FIG. 4 is a detail view of the portion of the fluid delivery catheter ofFIG. 1 indicated by the circle 1-1, showing the micro-needles in anextended position;

FIG. 5 is a cross-sectional view of the portion of the fluid deliverycatheter of FIG. 4;

FIG. 6 is a detail view of the portion of the fluid delivery catheter ofFIG. 3 positioned within a hollow anatomical structure;

FIG. 7 is a detail view of the portion of the fluid delivery catheter ofFIG. 5 positioned within a hollow anatomical structure;

FIGS. 8 and 9 are cross-sectional views of an alternative technique fordeploying the micro-needles of the fluid delivery catheter of FIG. 2.

DETAILED DESCRIPTION

The following detailed description describes the present embodimentswith reference to the Figures. In the Figures, reference numbers labelelements of the present embodiments. These reference numbers arereproduced below in connection with the discussion of the correspondingFigures' features. These figures, and their written descriptions,indicate that certain components of the apparatus are formed integrally,and certain other components are formed as separate pieces. Those ofordinary skill in the art will appreciate that components shown anddescribed herein as being formed integrally may in alternativeembodiments be formed as separate pieces. Those of ordinary skill in theart will further appreciate that components shown and described hereinas being formed as separate pieces may in alternative embodiments beformed integrally. Further, as used herein the term integral describes asingle unitary piece.

The present embodiments include a fluid delivery catheter that usesmicro-needles for fluid delivery though a vessel wall. The catheter maybe configured to provide fluid delivery therapy for various procedures,such as, for example, delivery of tumescent fluid or renal denervation.One advantage of the present catheter is its ability to efficiently andsimultaneously deliver fluid therapy from within a vessel lumen to thevessel wall or just outside the vessel wall via multiple targeteddelivery areas. The catheter includes an elongate member with deployableand retractable needles disposed about a distal end of the elongatemember. The needles may be disposed radially about the distal end and/oralong a length of the distal end.

FIG. 1 illustrates one example embodiment of the present fluid deliverycatheter 10. The catheter 10 comprises a flexible elongate member 12defining an internal lumen (not shown). A proximal end 14 of thecatheter 10 may include a female coupler 16 configured to receive asource of therapeutic fluid (not shown). For example, the female coupler16 may comprise a female luer lock fitting configured to receive asyringe having a corresponding male luer lock fitting.

The catheter 10 is preferably sized and configured to be advancedthrough a patient's target vessel lumen, such as the vasculature, froman access site on the body to a treatment site within the vasculature.Example dimensions for the catheter 10 include an outside diameter ofapproximately 8 French, or in the range of 4 French to 12 French, and alength in the range of 50 cm-200 cm, or about 80 cm, or about 120 cm.Material(s) from which the catheter 10 is constructed is preferablyrigid enough to enable it to be pushed distally through the vasculature,but flexible enough to enable navigation of tortuous vasculature.Example materials for the catheter 10 include polyurethane, polyetherblock amide (PEBAX™), or any lubricious and/or hydrophilic polymer suchas nylon, polyethylene or EVA. One suitable composition may comprise 39%Pebax 63D, 39% Pebax 72D, 20% BaSO₄, and 2% TiO₂.

With continued reference to FIG. 1, a distal portion of the catheter 10comprises a treatment length 18. The treatment length 18 may be aunitary extension of the catheter 10, or may be a discrete portionsecured to the catheter 10. The treatment length 18 is illustrated inthe detail views of FIGS. 2-5.

With reference to FIGS. 2 and 3, the treatment length 18 comprises anouter sleeve 20 and an inner lining 22. With reference to FIG. 3, theouter sleeve 20 comprises a tubular member defining a sleeve lumen 19with a closed distal end 26. The sleeve 20 includes a sidewall having aplurality of spaced apertures 28. In the illustrated embodiment, theapertures 28 are circular, but in other embodiments the apertures 28 maydefine any shape.

Further, in the illustrated embodiment, the apertures 28 are spaced bothalong a longitudinal axis of the treatment length 18 and about acircumference of the treatment length 18. With reference to FIG. 2, theapertures 28 may trace a helix H about the treatment length 18, whereineach aperture 28 is spaced 90° circumferentially from each adjacentaperture 28 as measured along the longitudinal axis of the treatmentlength 18, and only one aperture 28 is positioned at any given pointalong the longitudinal axis of the treatment length 18. However, inalternative embodiments the apertures 28 could have any spacing. Forexample, a plurality of apertures 28 could be positioned at any givenpoint along the longitudinal axis of the treatment length 18, with theplurality of apertures 28 spaced from one another about thecircumference of the treatment length 18.

The outer sleeve 20 is preferably made of a material that is flexibleand non-pressure-expandable, meaning that when a pressurized fluid isdelivered to the interior of the outer sleeve 20 it will not expandappreciably as the pressure increases. As the pressure continues toincrease toward the failure point of the outer sleeve 20, some expansionmay occur as the outer sleeve 20 fails. However, such an outer sleeve 20is still considered to be non-pressure-expandable. Example materials forthe outer sleeve 20 include, without limitation, polymers such aspolyurethanes in various durometers, polyether block amide (such asPEBAX®), thermoplastic polyurethane (TPU), polyethylene, or any othermaterial.

With reference to FIGS. 2 and 3, the inner lining 22 comprises a tubularmember defining a lining lumen 24. The lining 22 is received within thesleeve lumen 19 of outer sleeve 20, and includes a sidewall having adiameter such that the lining 22 abuts an inner surface of the sleevelumen 19 along the entire treatment length 18. The lining 22 may extendthe entire length of the elongate member 12 or only the length of thetreatment length 18, or any portion thereof. The lining lumen 24 isgenerally aligned with the lumen of the elongate member 12 if the lining22 is less than the full length of the elongate member 12. Withreference to FIG. 3, the lining 22 includes a plurality of independentlypressure-deformable portions 30 whose positions correspond to theapertures 28 in the outer sleeve 20. In the illustrated embodiment, eachof the pressure-deformable portions 30 is shaped as a hollow conicalfrustum, open on one end, with a base 32 that is recessed within itsrespective aperture 28. In other embodiments, the pressure-deformableportions 30 may define any shape. A diameter of the base 32 is less thana diameter of its corresponding aperture 28, such that a sidewall 34 ofeach pressure-deformable portion 30 tapers inwardly from the aperture 28to the base 32.

With reference to FIGS. 2-5, the pressure-deformable portions 30 aremovable between a retracted position (FIGS. 2 and 3) and an extendedposition (FIGS. 4 and 5). The retracted position represents an at-restconfiguration of the lining 22, which prevails when the pressure withinthe lining 22 is less than or equal to the ambient pressure. When apressurized fluid is delivered into the lining lumen 24 of the lining22, upon reaching a threshold pressure the pressure-deformable portions30 “pop” radially outward to the extended position in which theyprotrude from the outer surface of the outer sleeve 20 (FIG. 4). Invarious embodiments, the threshold pressure may be in the range of1-1,000 psi, such as 2-20 psi. The pressure-deformable portions 30 arefurther biased toward the retracted position, such that when thepressure within the lining 22 drops below the threshold pressure thepressure-deformable portions 30 “pop” radially inward to the retractedposition.

The inner lining 22 is preferably made of a material that is flexible toenable movement between the retracted and extended positions, butelastomeric with a memory to facilitate inward biasing towards theretracted position. Example materials for the inner lining 22 include,without limitation, polymers such as polyurethanes in variousdurometers, or any other material.

With reference to FIGS. 4 and 5, the treatment length 18 furthercomprises a plurality of micro-needles 36. Each micro-needle 36 issecured to the base 32 of one of the pressure-deformable portions 30,with one micro-needle 36 per pressure-deformable portion 30. In oneembodiment, the micro-needles 36 may be bonded or welded directly toeach base 32. In another embodiment, with reference back to FIG. 3, anunderside of each base 32 (on the interior side of the lining 22) mayinclude an abutting needle anchor 38. Each needle anchor 38 may be athin disk of a rigid or semi-rigid material. Each micro-needle 36 isembedded in a center of a corresponding one of the needle anchors 38,similar to a thumbtack, and extends through the base 32 of thecorresponding one of the pressure-deformable portions 30. Each needleanchor 38 may be secured to its respective base 32 by any suitablemeans, such as with adhesive, ultrasonic welding, or laser spot welding.Each needle may be sized in length to penetrate into the target vessel.In other embodiments, each needle may be sized in length to penetratebeyond the target vessel to deliver fluid outside the target vessel. Instill other embodiments, the length of the needles may be mixed toenable delivery of fluid both into and outside of the target vessel.

With reference to FIG. 4, each micro-needle 36 includes an internalneedle lumen (not shown), and a sharp distal tip 40. The needle lumen isexposed at its proximal end (the end embedded in the needle anchor 38)so that the needle lumen is in fluid communication with the lining lumen24 of the lining 22. Thus, when the pressurized fluid is introduced intothe lining lumen 24, the pressurized fluid not only causes thepressure-deformable portions 30 to move to the extended position, butalso the fluid to flow through the needle lumens and out the distal tips40 of the micro-needles 36. The treatment length 18 can thus be used toinject a therapeutic fluid into a hollow anatomical structure (HAS) byintroducing the therapeutic fluid into the lining lumen 24 underpressure, as described below. The needle lumens may be sized smallenough to enable a build-up of pressure within the lining 22 to causethe pressure-deformable portions 30 to move to the extended positionbefore significant amounts of the therapeutic fluid are deliveredthrough the needle lumens. The internal diameter of the needle lumen maybe balanced against the shape of the pressure-deformable portions 30 tocalibrate the pressure necessary to move the pressure-deformableportions 30 to the extended position. For example, with the materialsand material thickness being the same for both examples, thepressure-deformable portions 30A shown in FIG. 3A would require morepressure to move to the extended position that the pressure-deformableportions 30B shown in FIG. 3B. Thus, the needle 36A may have a needlelumen with a smaller internal diameter than the internal diameter of theneedle lumen of the needle 36B to enable more pressure to build withinthe lining 22.

A method of using the present fluid delivery catheter 10 is illustratedwith reference to FIGS. 6 and 7. An operator gains vascular access at anaccess site. For example, and without limitation, in a procedure such asdenervation of the renal artery, the access site may be located alongthe femoral artery, and the access method may be percutaneous access.Before or after gaining access , the operator may flush or prime thelumen of the elongate member 12 and the lining lumen 24 with saline orthe therapeutic fluid before putting the catheter 10 into thevasculature.

After gaining vascular access, the operator may advance the catheter 10through the vasculature to the treatment site. The operator may useexternal imaging, such as ultrasound or fluoroscopy, to aid in guidingthe catheter 10 to the treatment site. During the catheter 10advancement phase, the catheter 10 is in the configuration of FIG. 3,with the micro-needles 36 retracted.

With reference to FIG. 6, after the treatment length 18 has reached thetreatment site and is in the desired position within the vessel 42, theoperator connects a source of therapeutic fluid to the female coupler 16at the proximal end 14 of the catheter 10 (FIG. 1). The source oftherapeutic fluid may be, for example, a syringe. The operator theninjects the therapeutic fluid through the elongate member 12 and intothe lining lumen 24 of the inner lining 22. The therapeutic fluid may beany liquid or gas that may be injected into or around a vessel toproduce an effect on the vessel or surrounding tissue, such as tumescentfluid, sclerosant agents, medicants or drugs. As fluid pressure buildswithin the lining lumen 24, upon reaching a threshold pressure thepressure-deformable portions 30 “pop” radially outward to the extendedposition, causing the micro-needles 36 to penetrate the wall of thevessel 42, as shown in FIG. 7. As fluid continues to flow distallythrough the lining lumen 24 of the inner lining 22, it flows outwardthrough the micro-needles 36, thus delivering the therapeutic fluid tothe treatment site. In some embodiments in which the lining lumen 24 isflushed with the therapeutic fluid prior to being inserted into thevasculature, the injection fluid of the foregoing step may comprisesaline or some other benign fluid.

In certain embodiments, the operator may inject tumescent anesthesia atthe treatment site prior to delivering the therapeutic fluid into thelining lumen 24. The tumescent anesthesia compresses the vessel 42 atthe treatment site to facilitate penetration of the vessel wall by themicro-needles 36 when the therapeutic fluid is injected into the lininglumen 24. Other methods of compressing the vessel 42, such as externallyapplied manual compression, may also be used in addition to, or insteadof, tumescent anesthesia.

When the desired amount of therapeutic fluid has been delivered, theoperator ceases injecting fluid. As fluid pressure within the lumen 24drops, upon reaching the threshold pressure, the pressure-deformableportions 30 “pop” radially inward to the retracted position due to theirradially inward bias, as shown in FIG. 6. The operator subsequentlywithdraws the catheter 10 from the vessel 42 and concludes the treatmentprocedure by closing the access site.

As illustrated above, embodiments of the present fluid delivery catheter10 advantageously enable efficient and simultaneous delivery of fluidtherapy from within a vessel to areas just outside the vessel wall viamultiple targeted delivery areas. The longitudinal and circumferentialspacing of the micro-needles 36 enables wide dispersal of thetherapeutic fluid both along and around the vessel, thereby covering alarge treatment area in as little as one injection of therapeutic fluidwithout any need to translate or rotate the catheter 10 during theprocedure.

In an alternative embodiment, the pressure-deformable portions may bemoved to the extended position by a flexible wire advanced into andthrough the elongate member and into engagement with thepressure-deformable portions. Referring to FIGS. 8 and 9, an elongatewire 50 may include annular grooves 52 to enable fluid flow through thelumen of the elongate member 12 and the lining lumen 24. The annulargrooves 52 are configured to also enable fluid communication between thetherapeutic fluid in the lining lumen 24 and needle lumens. The annulargrooves 52 may be a plurality of individual circumferential grooves, ormay be helically wound along the length, or a portion of the length, ofthe elongate wire 50. As shown in FIG. 8, a distal end 54 of the wire 50engages the deformable portions 30 as the wire 50 is advanced along thelining lumen 24. The distal end 54 of the wire 50 is configured toenable smooth engagement with the deformable portions 30, such as arounded end or ramp 56. As the wire 50 is advanced further distally, thewire 50 pushes the deformable portion 30 to the extended position (FIG.9). Therapeutic fluid may then be injected into the elongate member 12,along the lumen of the elongate member, and into the lining lumen 24,where the fluid may then pass out the needle lumens. When the procedureis completed, the wire 50 is retracted proximally, and the deformableportions 30 will return to the retracted position automatically due toinward bias of the deformable portions 30. The wire 50 has the benefitof enabling the needles 36 to have a larger needle lumen for thedelivery of more fluid quickly because the fluid is not required tobuild the pressure in the lining 24 to move the deformable portions 30.

In another example embodiment, the wire 50 may have longitudinal groovesor flutes along the length of the wire 50. The longitudinal grooves,like the annular grooves 52, enable fluid flow around the wire and intothe needle lumens.

It is to be understood that the foregoing description is intended toillustrate and not limit the scope of the invention, which is defined bythe scope of the appended claims. Other embodiments are within the scopeof the following claims.

What is claimed is:
 1. A method of delivering a fluid at a treatmentsite within a hollow anatomical structure (HAS), the method comprising:positioning a treatment length of an elongate catheter at the treatmentsite, the treatment length including an outer sleeve defining aplurality of spaced apertures and a sleeve lumen; a flexible innerlining defining a plurality of independently pressure-deformableportions and a lining lumen disposed within the sleeve lumen, whereineach of the plurality of pressure deformable portions are generallyaligned with one of the plurality of spaced apertures; and a pluralityof micro-needles, each micro-needle being secured to one of thepressure-deformable portions and in fluid communication with the lininglumen, wherein the pressure-deformable portions and the micro-needlesare recessed beneath an outer surface of the outer sleeve in an at-reststate; deforming the pressure-deformable portions to an extendedposition in which at least a portion of the micro-needles protrude abovethe outer surface of the outer sleeve to penetrate a wall of the HAS;and delivering the fluid under pressure into the lining lumen, throughneedle lumens of the micro-needles and into the HAS wall.
 2. The methodof claim 1, wherein the pressure-deformable portions are deformed to theextended position by the pressurized fluid delivered into the lininglumen.
 3. The method of claim 1, wherein the pressure-deformableportions are deformed to the extended position by an elongate wire, theelongate wire comprising at least one of annular grooves or longitudinalgrooves.
 4. The method of claim 1, wherein the therapeutic fluid flowsinto the HAS wall at a plurality of locations simultaneously, theplurality of locations corresponding to positions of the plurality ofmicro-needles.
 5. The method of claim 2, further comprising ceasingdelivery of the therapeutic fluid to cause the pressure-deformableportions to retract radially inward such that the micro-needles arerecessed beneath the outer surface of the outer sleeve.
 6. The method ofclaim 1, wherein the pressure-deformable portions are spaced from oneanother along a longitudinal axis of the treatment length and about acircumference of the treatment length.
 7. The method of claim 6, whereinpositions of the pressure-deformable portions trace a helix about thetreatment length.
 8. The method of claim 1, further comprising injectingtumescent anesthesia to the treatment site prior to delivering thetherapeutic fluid under pressure.